#include "Mystdio.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <assert.h>
#include <unistd.h>

#define FILE_MODE 0666

_FILE* _fopen(const char* filename,const char* flag)
{
	assert(filename);
	assert(flag);

	int f = 0;
	int fd = -1;
	if(strcmp(flag,"w") == 0) 
	{
		f = (O_CREAT|O_WRONLY|O_TRUNC);
		fd = open(filename,f,FILE_MODE);
	}
	else if(strcmp(flag,"a") == 0)
	{
		f = (O_CREAT|O_WRONLY|O_APPEND);
		fd = open(filename,f,FILE_MODE);
	}
	else if(strcmp(flag,"r") == 0)
	{
		f = O_RDONLY;
		fd = open(filename,f);
	}
	else return NULL;
	if(fd == -1) return NULL;

	_FILE* fp = (_FILE*)malloc(sizeof(_FILE));
	if(fp == NULL) return NULL;

	fp->fileno = fd;
	fp->flag = FLUSH_LINE;
	fp->out_pos;
	return fp;
}

int _fwrite(_FILE* fp,const char* str,int len)
{
	memcpy(&fp->outbuffer[fp->out_pos],str,len);
	fp->out_pos += len;

	if(fp->flag & FLUSH_NOW)
	{
		write(fp->fileno,fp->outbuffer,fp->out_pos);
		fp->out_pos = 0;
	}
	else if(fp->flag & FLUSH_LINE)
	{
		if(fp->outbuffer[fp->out_pos-1] == '\n')
		{
			write(fp->fileno,fp->outbuffer,fp->out_pos);
			fp->out_pos = 0;
		}
	}
	else if(fp->flag & FLUSH_ALL)
	{
		if(fp->out_pos == SIZE)
		{
			write(fp->fileno,fp->outbuffer,fp->out_pos);
			fp->out_pos = 0;
		}
	}
	return len;
}

void _fflush(_FILE* fp)
{
	if(fp->out_pos>0)
	{
		write(fp->fileno,fp->outbuffer,fp->out_pos);
		fp->out_pos = 0;
	}
}

void _fclose(_FILE* fp)
{
	if(fp == NULL) return;
	_fflush(fp);
	close(fp->fileno);
	free(fp);
}
